1. Field of the Invention
The present invention relates in general to scalable video compression and more particularly to a system and method for encoding, transmitting, decoding and storing a video sequence such as High Definition television signals (HDTV) using a base layer and an enhancement layer.
2. Description of Related Art
Scalable Coding of video refers to compression techniques that result in a compressed bitstream in which one or more subsets of the whole bitstream can be decoded at reduced quality (such as reduced resolution, frame rate, or bit-rate). Scalable coding techniques have been present in most video compression standards, including MPEG-1 and MPEG-2. Examples of scalable video coding include compression of a High Definition (HD) bitstream in which a Standard Definition (SD) subset can be decoded, or compression of a 60 Hz bitstream in which a 30 Hz subset can be decoded.
A particular application of scalable video compression arises because many TV operators are planning to deploy 1080P @60 Hz video services in the next few years. This format is what is used by most of the high-end consumer HD displays currently being purchased. The fact that this format is scanned progressively eliminates the need for deinterlacing within the consumer display, and the 1080 line format offers higher resolution than the 720P format.
However, millions of HD decoders already have been deployed by the TV operators, and this installed base of decoders only can decode 720P @60 Hz or 1080I @60 Hz format video. Operators would like to be able to deliver 1080P content to next-generation receivers while still delivering the same content to their legacy receivers. To simulcast the old and new formats is expensive in bit-rate, and scalable coding offers an attractive solution.
The Joint Video Team (JVT) of the ISO/MPEG group and the ITU-T have developed a Scalable Video Coding (SVC) standard based on H.264/AVC. This standard includes a great deal of flexibility for scalable coding of video, and its compression tools offer high efficiency. However, the complexity of the SVC technology is high, both for encoders and decoders.
A need therefore exists for a scalable video compression method for the legacy-vs-1080P application described above, without the complexity of the JVT SVC specification.